asked the u.n. to look into the claim. >> the demand came after both sides accused each other of firing chemical weapons on tuesday. opposition groups insist rebels don't have access to such material. >> and u.s. officials saying they welcome the move. >>> first up, north korea's new and threatening message. pyongyang warning today it has the capability to strike u.s. bases in guam and japan. >> matthew chance joining us now from seoul, south korea. matthew, is this north korea's typical bluster or something more ominous here? >> it's really difficult to say, fredricka, because it's such an unpredictable regime. but what we do know is these threats are being made all the time now. there's a lot of tension that's been growing on the korean peninsula, tension that is being fueled by the statement that are increasingly coming out of pyongyang. barely a day can pass it seems without another north korean threat. state television is full of them. the latest in response to u.s. bomber flights over south korea. it's an annual military exercise but pyongyang is seething. >> translator: the u.s.